Disk player, and self-compensating-dynamic-balancer (SCDB) integrated turntable, SCDB integrated clamper and SCDB integrated spindle motor employed in the same

ABSTRACT

A disk player having a self-compensating dynamic balancer so as to subdue internal vibrations due to an eccentric center of mass of a disk, a self-compensating-dynamic-balancer integrated turntable, a self-compensating-dynamic-balancer integrated clamper, and a self-compensating-dynamic-balancer integrated spindle motor which are employed in the disk player. The self-compensating dynamic balancer is embodied by forming a cavity in a turntable, clamper, a rotor of a spindle motor, or the like, and disposing movable members including movable rigid bodies and/or a liquid therein. Internal vibrations due to the eccentric mass of the disk are subdued effectively the movable members moving away from a revolution center according to respective centrifugal forces where the self-compensating dynamic balancer rotates.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This is a divisional of application Ser. No. 09/955,046 filedSep. 19, 2001, now allowed, and claims the benefit of Korean ApplicationNo. 2000-79735 filed Dec. 21, 2000, in the Korean Patent Office, thedisclosures of which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to a disk player, a turntable, aclamper and a spindle motor which are employed in the disk player, andmore particularly, to a disk player provided with a self-compensatingdynamic balancer so that internal vibrations due to eccentric mass of adisk can be limited, a self-compensating-dynamic-balancer integratedturntable, a self-compensating-dynamic-balancer integrated clamper, anda self-compensating-dynamic-balancer integrated spindle motor which areemployed in the disk player.

[0004] 2. Description of the Related Art

[0005] In general, a disk player is an apparatus for recordinginformation on a recording medium such as a compact disk (CD), a CD-ROM,or a digital versatile disk (DVD), or reproducing information recordedfrom the recording medium. The disk and an optical pickup are requiredto be protected against external impact and internal vibrations.

[0006] A conventional disk player is shown in FIG. 1. A deck base 10 ishinged to a housing (not shown) to pivot in a vertical direction and adeck plate 20 is attached to the deck base 10. A spindle motor 21,installed at the deck plate 20 to provide a rotational force for a disk1, has a turntable 23 fixed to a shaft 22 of the spindle motor 21. Adisk 1 is placed on the turntable 23. A clamper 40 is installed at theupper inner surface of the housing to face the turntable 23 for clampingthe disk 1 on the turntable 23, and an optical pickup 25 is installed atthe deck plate 20 to be movable in a radial direction of the disk 1 forperforming recording and reproducing operations. The disk player isprovided with damper members 30 installed between the deck base 10 andthe deck plate 20 so that external vibrations transferred via the deckbase 10 are not transferred directly to the deck plate 20, the spindlemotor 21 and the optical pickup 25. The damper members 30 are made of amaterial not having a high strength, such as a soft rubber orpolyurethane, so as to absorb external impacts well.

[0007] The disk player of FIG. 1 protects the disk 1 and the opticalpickup 25 from external impact by employing the damper members 30.However, the disk player of FIG. 1 includes no measures for reducinginternal vibrations occurring due to an eccentric mass of the disk 1where the spindle motor 21 rotates. Here, the eccentric mass of the diskis produced by variations in a manufacturing process of the disk 1. Theeccentric mass causes whirling, that is, the revolution of the rotationaxis of the spindle motor due to a disparity between the center ofrotation of the disk 1 and the center of mass of the disk.

[0008] The influence of whirling on the spindle motor 21 is notsignificant in a low-speed model, such as a base- or a dual-speed model,but the whirling influence is so serious in a high speed model, such asa six-speed or eight-speed model, that recording/reproduction ofinformation can be difficult. To compensate for the whirling influencein a conventional high speed disk player, a deck plate at which aspindle motor is installed is made to have a greater mass, or the dampermembers are made stronger so that undesirable movement of a deck platedue to an eccentric mass of a disk is reduced.

[0009] The effect on whirling of increasing the mass of the deck plateis insignificant where the disk player operates at a high speed.Additionally, an increase in mass increases manufacturing cost, andlimits compactness of the disk player. Where the damper members strengthis increased, the damper members do not effectively block vibrations andimpact transferred from outside the disk player.

SUMMARY OF THE INVENTION

[0010] To solve the above problems, it is a first object of the presentinvention to provide a disk player which limits internal vibrations dueto eccentric mass of a disk without increasing the mass of the diskplayer and which reduces an influence of external vibrations.

[0011] It is a second object of the present invention to provide aself-compensating-dynamic-balancer integrated turntable employable in adisk player to limit internal vibrations due to eccentric mass of adisk.

[0012] It is a third object of the present invention to provide aself-compensating-dynamic-balancer integrated clamper employable in adisk player to limit internal vibrations due to eccentric mass of adisk.

[0013] It is a fourth object of the present invention to provide aself-compensating-dynamic-balancer integrated spindle motor employablein a disk player to limit internal vibrations due to eccentric mass of adisk.

[0014] Additional objects and advantages of the invention will be setforth in part in the description which follows, and, in part, will beobvious from the description, or may be learned by practice of theinvention.

[0015] Accordingly, to achieve the first and other objects, there isprovided a disk player comprising: a deck base; a deck plate elasticallyattached to the deck base; damper members interposed between the deckbase and the deck plate so that the deck plate can be protected fromexternal impact; a spindle motor installed at the deck plate forproviding rotational force to a disk; a turntable which is installed onthe rotation shaft of the spindle motor, and on which the disk isplaced; a clamper for clamping the disk placed on the turntable; anoptical pickup installed on the deck plate for recording and/orreproducing information on/from the disk; and a self-compensatingdynamic balancer which is installed in a cavity provided in at least onerotating member and the center of mass thereof is disposed at a positionopposite the center of mass of the disk with respect to the rotationshaft of the spindle motor due to respective centrifugal forces wherethe disk rotates, wherein external vibrations are prevented from beingtransferred to the deck plate by the damper members, and internalvibrations generated by an eccentric center of mass of the disk arelimited by the self-compensating dynamic balancer.

[0016] To achieve the second and other objects, there is provided aself-compensating-dynamic-balancer integrated turntable for a diskplayer comprising: a cylindrical turntable main body fixed to therotation shaft of a spindle motor and provided with a cavity therein;movable members movably disposed in the cavity; and a cover memberjoined to an opening of the main body so as to cover the main body, andprovided with an engagement projection on the upper surface thereof towhich the center hole of the disk is fitted so that the disk can beseated thereon.

[0017] To achieve the third and other objects, there is provided aself-compensating-dynamic-balancer integrated clamper for a disk playercomprising: a cylindrical clamper main body installed on a deck base tobe rotated by a rotational force of a spindle motor, and provided with acavity; a pressing member installed at the clamper main body forpressing a disk placed on a turntable; movable members movably disposedin the cavity of the clamper main body; and a cover member joined to anopening of the main body for covering the cavity.

[0018] To achieve the fourth and other objects, there is provided aself-compensating-dynamic-balancer integrated spindle motor for a diskplayer comprising: a motor base to be screwed to a deck plate; a statorfixed to the motor base; a rotor installed to be rotatable with respectto the stator; a cylindrical case attached to the rotor to form a cavitytherebetween, and movable members movably disposed in the case.

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The above objects and advantages of the present invention willbecome more apparent by describing in detail preferred embodimentsthereof with reference to the attached drawings in which:

[0020]FIG. 1 is an exploded perspective view illustrating a conventionaldisk player;

[0021]FIG. 2 is an exploded perspective view schematically illustratinga disk player according to the present invention;

[0022]FIGS. 3A, 3B and 3C are schematic diagrams illustrating positionalrelations of positions of eccentric mass of a disk with positions of arotation shaft with respect to a revolution center depending onrotational speeds of a disk;

[0023]FIG. 4 is a cut-away perspective view illustrating an embodimentof a self-compensating balancer employed in a disk player according tothe present invention;

[0024]FIG. 5 is a schematic sectional view of FIG. 4 where rigid bodiesare employed as movable members;

[0025]FIG. 6 is a schematic sectional view of FIG. 4 where rigid bodiesand a fluid are employed as movable members;

[0026]FIGS. 7, 8 and 9 are perspective views each showing a portion of aself-compensating balancer and illustrating rigid body shapes ofspherical, cylindrical and conical, respectively, employed as themovable members;

[0027]FIG. 10 is an exploded perspective view showing a portion of aself-compensating balancer and illustrating a sectorial pillar shaperigid body employed as the movable members;

[0028]FIG. 11 is a sectional view illustrating a diametrical section ofa cavity of a self compensating dynamic balancer wherein the section hasa rectangular shape;

[0029]FIG. 12 is a sectional view illustrating a diametrical section ofa cavity of a self-compensating dynamic balancer wherein the section hasa dumbbell shape;

[0030]FIG. 13A is a sectional view illustrating a diametrical section ofa cavity of a self-compensating dynamic balancer wherein the section hasopposing sides with a hyperbolic shape;

[0031]FIG. 13B is a sectional view illustrating a diametrical section ofa cavity of a self-compensating dynamic balancer wherein the section hasa straight side and an opposing side of a hyperbolic shape;

[0032]FIG. 14 is a sectional view illustrating a diametrical section ofa cavity of a self-compensating dynamic balancer wherein the section hasopposing sides of an elliptical shape;

[0033]FIG. 15 is an exploded perspective view illustrating a firstembodiment of a self-compensating-dynamic-balancer integrated turntablefor a disk player according to the present invention;

[0034]FIG. 16 is a sectional view of theself-compensating-dynamic-balancer integrated turntable illustrated inFIG. 15, wherein rigid bodies and a fluid are employed as movablemembers;

[0035]FIG. 17 is a sectional view illustrating a second embodiment of aself-compensating-dynamic-balancer integrated turntable for a diskplayer according to the present invention;

[0036]FIG. 18 is a sectional view illustrating a third embodiment of aself-compensating-dynamic-balancer integrated turntable for a diskplayer according to the present invention;

[0037]FIG. 19 is an exploded perspective view illustrating a firstembodiment of a self-compensating-dynamic-balancer integrated clamperfor a disk player according to the present invention;

[0038]FIG. 20 is a sectional view of theself-compensating-dynamic-balancer integrated clamper illustrated inFIG. 19, wherein a yoke is employed as a pressing member;

[0039]FIG. 21 is a sectional view of theself-compensating-dynamic-balancer integrated clamper illustrated inFIG. 19, wherein an elastic member is employed as a pressing member;

[0040]FIG. 22 is a sectional view of theself-compensating-dynamic-balancer integrated clamper illustrated inFIG. 19, wherein rigid bodies and a fluid are employed as movablemembers;

[0041]FIG. 23 is an exploded perspective view illustrating an embodimentof a self-compensating-dynamic-balancer integrated spindle motor for adisk player according to the present invention;

[0042]FIG. 24 is a sectional view of theself-compensating-dynamic-balancer integrated spindle motor illustratedin FIG. 23, wherein rigid bodies are employed as movable members;

[0043]FIG. 25 is a sectional view of theself-compensating-dynamic-balancer integrated spindle motor illustratedin FIG. 23, wherein rigid bodies and a fluid are employed as movablemembers; and

[0044]FIGS. 26 and 27 are schematic diagrams illustrating positionalrelations of positions of eccentric mass of a disk with positions of arotation shaft with respect to a revolution center depending onrotational speeds of the disk, respectively, in a disk player having aself-compensating dynamic balancer according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0045] Reference will now be made in detail to the present embodimentsof the present invention, examples of which are illustrated in theaccompanying drawings, wherein like reference numerals refer to likeelements throughout.

[0046] As shown in FIG. 2, a disk player 10 according to a firstembodiment of a self-compensating-dynamic-balancer-disk player of thepresent invention comprises: a deck base 50, a deck plate 70 elasticallyattached to the deck base 50, damper members 60 interposed between thedeck base 50 and the deck plate 70, a spindle motor 100 installed at thedeck plate 70, a turntable 200, an optical pickup 75, a clamper 300installed to face the turntable 200 for clamping a disk 1 placed on theturntable 200, and a self-compensating dynamic balancer (SCDB) 400 forrestraining the revolution of the rotation axis of the spindle motor 100due to eccentric mass of the disk 1.

[0047] The deck plate 70 experiences impact which is transferred fromoutside the disk player 10 via the deck base 50, and which is dampenedby the damper members 60. Damper members 60 are preferably made of amaterial, such as a soft rubber or polyurethane, so as to reduceexternal vibrations transferred via the deck base 50. Also, the deckplate 70 is preferably light in weight. The spindle motor 100 provides arotational force for rotating the disk 1. The center of the turntable200 is fixed to a shaft 130 of the spindle motor 100, and where the diskplayer 10 is operated, the disk 1 is placed on the turntable 200. Theclamper 300, installed on a bracket 301 and facing the spindle motor100, prevents the disk 1 placed on the turntable 200 from moving freely.The turntable 200 is fixed to the shaft 130, and is rotated by thespindle motor 100, and accordingly the disk 1 and the clamper 300 rotatetogether with the turntable 200. The positional relations of aneccentric mass of the disk 1, the rotation center of the disk 1 and thecenter of revolution according to various rotational speeds of the disk1 will be described with reference to FIGS. 3A through 3C.

[0048]FIG. 3A is a schematic diagram illustrating revolutionary androtational motions of the disk 1 where a rotational frequency of thespindle motor is less than a natural frequency of the deck plate 70.Here, the natural frequency is determined by the elastic modulus of thedamper members 60 and masses of the deck plate 70 and members installedat the deck plate 70, and refers to the natural frequency in a directionparallel to major faces of the disk 1. As shown in FIG. 3A, where anunbalanced mass, that is, an eccentric center of mass m_(e) of the disk1 exists at a position P₁ spaced a predetermined distance from therotation center C₁ of the disk 1, the rotation center C₁ of the disk 1is displaced to points C₂, C₃, and C₄ in sequence with a revolutioncenter C as a datum point, and revolves about the datum point. Theposition of the eccentric center of mass me of the disk 1 is displacedto points P₂, P₃, and P₄ in sequence corresponding to the rotationcenters C₂, C₃, and C₄. As the disk revolves, the positions P₁, P₂, P₃,and P₄ of the eccentric mass m_(e) of the disk 1 are positioned oppositethe revolution center C with respect to the rotation centers C₁, C₂, C₃,and C₄ of the disk 1, respectively.

[0049]FIG. 3B is a schematic diagram illustrating the revolutionary androtational motions of the disk 1 where the rotational frequency of thespindle motor 100 is similar to the natural frequency of the deck plate70. Referring to FIG. 3B, the revolution center C, the rotation centerC₁ and the position P₁ of the eccentric center of mass m_(e) of the disk1 form a right angle (C-C₁-P₁). Likewise, C-C₂-P₂, C-C₃-P₃, and C-C₄-P₄also form right angles.

[0050]FIG. 3C is a schematic diagram illustrating the revolutionary androtational motions of the disk 1 where the rotational frequency of thespindle motor 100 is larger than the natural frequency of the deck plate70. The normal rotation speed of the disk enabling information to bewritten/reproduced onto/from the disk 1 falls into this case, and thepositions P₁, P₂, P₃ and P₄ of the eccentric center of mass m_(e) of thedisk 1 and the revolution center C with respect to the rotation centersC₁, C₂, C₃, and C₄ of the disk 1, respectively, are points alongstraight lines P₁-C-C₁, P₂-C-C₂, P₃-C-C₃ and P₄-C-C₄, respectively.

[0051] As described above, the present invention is characterized inthat the self-compensating dynamic balancer 400 (FIG. 2) is provided soas to compensate for dynamic unbalance of a disk by using therelationship between the revolution center of the disk 1 and theeccentric center of mass of the disk 1.

[0052] The self-compensating dynamic balancer 400 is incorporated intoat least any one rotating member of the disk drive, such as for example,the spindle motor 100, the rotation shaft 130, the turntable 200 and theclamper 300, wherein the at least one rotating member is rotated by therotational force supplied by the spindle motor 100. For exemplaryembodiments of the self-compensating-dynamic-balancer 400 incorporatedinto the various components of the disk player, see descriptions ofspindle motors 100 a and 100 b; turntables 200 a, 200 b and 200 c; andclampers 300 a, 300 b and 300 c, which are set forth below.

[0053] As shown in FIG. 4, a first embodiment of the self-compensatingdynamic balancer 400 comprises a cylindrical case 410 provided with acavity 450, and movable members 420 disposed in the cavity 450. The case410 comprises a main body 412 and a cover member 413. The cover member413 is attached to the main body 412 using an adhesive, pairs of groovesand protrusions formed at corresponding positions, screws or otherattachment apparatus or methods. Since a suitable attachment apparatusand methods are well-known, detailed descriptions thereof will beomitted.

[0054] The movable members 420 are free to move away from the rotationcenter according to respective centrifugal forces thereon where the case410 rotates. The movable members 420 comprise one of a plurality ofrigid bodies 430, a fluid 440 such as a liquid, and a plurality of rigidbodies 430 and the fluid 440. The movable members 420 function as amigrating mass having a movable mass center which shifts under theinfluence of the centrifugal forces to compensate for the eccentric massm_(e) of the disk 1 and the migrating mass rotates synchronously withthe disk 1 to attenuate vibrations induced by the eccentric center ofmass m_(e) of the disk 1.

[0055]FIG. 5 shows an example of the self-compensating dynamic balancer400 comprising the plurality of rigid bodies 430 disposed in the cavity450 of the case 410 as the movable members 420. The rigid bodies 430 areinstalled to roll or slide freely so that positions of the rigid bodiesare determined by respective centrifugal forces where the case 410rotates.

[0056]FIG. 6 shows another example of a self-compensating dynamicbalancer 400 in which the movable members 420 comprise the plurality ofrigid bodies 430 and the fluid 440. Since the fluid 440 has a largercontacting area with the main body 412 and the cover member 413 than therigid bodies 430, the eccentric center mass of the disk 1 (FIG. 2) whichcauses internal vibrations is more effectively compensated. That is, thefluid 440 reduces friction between the rigid bodies 430 and inner wallsof the case 410 and exerts damping forces against the rigid bodies 430,thus, retarding the rigid bodies 430 from moving violently before therigid bodies 430 find their balanced positions. Most of the revolutionof the rotation shaft 130 due to the eccentric center of mass of thedisk 1 (FIG. 2) is removed by movements of the rigid bodies 430, andfine compensation of the revolution is provided by movement of the fluid440.

[0057] An amount of fluid 440 may be just enough to provide a coating ofabout several-μm thickness on each rigid body 430. In this case, thefluid 440 serves as a lubricant to reduce friction between the rigidbodies 430 and the inner walls of the case 410, and to give the rigidbodies 430 a damping effect instead of taking a substantial part in abalancing operation.

[0058]FIGS. 7 through 10 are partially cut-away perspective viewsillustrating various exemplary shapes of embodiments of the rigid body430 which may be employed within the cavity 450 of the case 410.

[0059]FIG. 7 is a partially cut-away perspective view illustrating therigid body 430 as a spherical shaped rigid body 430-1.

[0060]FIG. 8 is a partially cut-away perspective view illustrating therigid body 430 as a cylindrical shaped rigid body 430-2. The cylindricalrigid body 430-2 is disposed so that the circumferential surface of thecylindrical rigid body 430-2 rolls over an inner wall surface 410 a ofthe case 410. Lower and upper planar surfaces of the cylindrical rigidbody 430-2 slide between inner wall surfaces 410 b and 410 c, thus,there is a possibility of increasing friction between the cylindricalrigid body 430-2 and the case 410. Taking this possibility of increasingfriction into consideration, the inner wall surfaces 410 b and 410 c ofthe cavity 450 of the case 410 preferably have an elliptical shape asshown in FIG. 14, as will be described more fully below.

[0061]FIG. 9 is a partially cut-away perspective view illustrating therigid body 430 as a conical frustum shaped rigid body 430-3. The rigidbody 430-3 is disposed so that the curved circumferential surfacethereof rolls between the inner wall surfaces 410 b and 410 c of thecase 410.

[0062]FIG. 10 is an exploded perspective view illustrating the rigidbody 430 as a sectorial pillar shaped rigid body 430-4. The rigid body430-4 is inserted so that the rigid body 430-4 slides along the innerwall surfaces 410 b and 410 c (not shown) and/or along the side wall 410a of the case 410.

[0063] Alternatively, the rigid body 430 included in the case 410 mayhave a shape different from the shapes of the rigid bodies 430-1, 430-2,430-3 and 430-4 as long as the rigid body 430 is allowed to move freelyin the cavity 450 of the case 410.

[0064] Since the rigid bodies 430 may not freely move due to interactionbetween adjacent rigid bodies 430 where the rigid bodies 430 are underinfluence of a magnetic field, the rigid bodies 430 are preferably madeof a non-magnetic material so that the rigid bodies 430 are notinfluenced by the magnetic field.

[0065] Examples of suitable non-magnetic materials for the rigid body430 include tungsten carbide, a copper-beryllium alloy, Hastelloy C-276,zirconia (ZrO₂), an austenitic stainless steel (YHD50), SUS300, SUS304,SUS316, or the like, a ceramic material such as silicon nitride, or asynthetic resin material. In addition, the rigid body 430 may be made ofa non-magnetic material such as bronze, brass, or copper, and platedwith nickel, chromium or the like by a surface treatment.

[0066] Where the rigid body 430 is not influenced by a magnetic field inthe vicinity thereof, the rigid body 430 moves depending on therotations of the rotating members which incorporate theself-compensating-dynamic-balancer 400 and the position of eccentriccenter of mass m_(e) of the disk 1 (FIG. 2).

[0067] The rigid body 430 is preferably made of an antioxidant material,or coated with an antioxidant material so that the rigid body 430 isprevented from erratically rolling or sliding in the cavity 450 of thecase 410 due to oxidation and corrosion of the rigid body 430.

[0068] The rigid body 430 may be made of an antioxidant material such asSUS300, a ceramic material, a synthetic resin material, or the like.Alternatively, a carbon steel, or an iron-chromium alloy may be used asa base metal to make the rigid body 430, and the outer surface thereofplated with zinc, nickel and/or chromium for anti-oxidation.

[0069] Alternatively, the rigid body 430 may be made of a material whoseoxide particle oxidated in air is fine enough to not affect the movementof the rigid body 430. The materials and coatings described for therigid body 430 are equally applicable to the spherical rigid body 430-1,the cylindrical rigid body 430-2, the conical frustum shaped rigid body430-3 and the sectorial pillar shaped rigid body 430-4.

[0070] Various shapes of the cavity 450 within the case 410 according toembodiments of the main body 412 and the cover member 413 of the case410 will be described with reference to FIGS. 11 through 14.

[0071] As shown in FIG. 11, a main body 412-1 and a cover member 413-1are configured so that a diametrical section of the cavity 450 in whichthe movable rigid bodies 430-1 are installed has a rectangular shape450-1.

[0072] As shown in FIG. 12, the diametrical section of the cavity 450may have a dumbbell shape 450-2 formed in a main body 412-2 and a covermember 413-2, wherein the movable rigid body 430-1 moves along a roundedannular portion 414 formed at a peripheral portion of the cavity 450while being guided by the rounded annular portion 414.

[0073] As shown in FIG. 13A, the diametrical section of the cavity 450may have a hyperbolic shape 450-3 formed in a main body 412-3 and acover member 413-3 wherein the cavity 450 has a narrow portion at acenter portion of the cavity 450 and gradually widens toward an outerportion of the cavity 450. The hyperbolic shape 450-3 is veryadvantageous for causing the rigid body 430-1 to move toward the outerportion, and for reducing a contact portion between the rigid body 430-1and the inner surfaces of the case 410. Alternatively, as shown in FIG.13B, the diametrical section of the cavity 450 may have ahalf-hyperbolic shape 450-4 formed in a main body 412-3 and a covermember 413-1 wherein one boundary of the shape 450-4 is one branch of ahyperbola and another boundary of the shape 450-2 is a straight line.

[0074] As shown in FIG. 14, the diametrical section of the cavity 450may have an elliptical shape 450-5 formed in a main body 412-4 and acover member 413-4 wherein two boundaries of the section are shaped as aportion of an ellipse, and wherein the cavity 450 is wide at a centerportion of the cavity 450 and gradually narrows toward outer portions ofthe cavity 450. In the elliptical shaped cavity, where the rigid body430-2 (FIG. 10) having a cylindrical shape is employed, sliding movementbetween the case 410 and the rigid body 430-2 is restrained.

[0075] The main body 412 and the cover member 413 of the case 410 arepreferably made of non-magnetic materials so as to prevent influence ofmagnetic forces interacting with the rigid bodies 430. That is, the mainbody 412 and the cover member 413 may be made of non-magnetic metallicmaterials such as tungsten carbide, a copper-beryllium alloy, HastelloyC-276, zirconia (ZrO₂), brass, an austenitic stainless steel (YHD50),SUS300, SUS304, SUS316, or the like, a ceramic material such as siliconnitride, or a synthetic resin material.

[0076] Also, the main body 412 is preferably made of an antioxidantmaterial or is coated with an antioxidant material. Suitable antioxidantmaterials include SUS 300, a ceramic material, a synthetic resinmaterial, or the like. The antioxidant coating is formed by plating witha thin layer of zinc, nickel or chromium, or the like on a base metalsuch as a carbon steel, or an iron-chromium alloy. The materials andcoatings described for the main body 412 and the cover member 413 arealso applicable to the main bodies 412-1, 412-2, 412-3, and 412-4 andthe cover members 413-1, 413-2, 413-3 and 413-4.

[0077] A first embodiment 200 a of a self-compensating-dynamic-balancerintegrated turntable according to the present invention will bedescribed with reference to FIGS. 15 and 16

[0078] Referring now to FIGS. 15 and 16, a cylindrical main body 210-1of the turntable 200 a is fixed to the rotation shaft 130 of a spindlemotor 100, which is installed through a motor base 110. A boss 240 isformed at a lower surface of the main body 210-1 and the rotation shaft130 is inserted into the boss 240. Movable members 270 are disposed in acavity 250 of the main body 210-1 so that the movable members 270 arefree to move away from a rotation center of the main body 210-1according to respective centrifugal forces developed where the turntable200 a rotates. The cavity 250 is sealed by assembling a cover member260-1 enclosing the movable members 270 in the cavity 250. An engagementprojection 220 is formed on an upper surface of the cover member 260-1to receive a center opening of the disk 1.

[0079] The cover member 260-1 is attached to the main body 210-1 byusing an adhesive, pairs of grooves and protrusions formed atcorresponding positions, screws or the like. Since attachment methodsare well-known, detailed descriptions thereof will be omitted. The upperopening of the main body 210-1 may be formed over the whole surface ofthe main body 210-1, as shown in FIGS. 15 and 16, or the upper openingmay be formed at a portion of the upper surface of the main body 210-1to have dimensions that allow the movable members 270 to pass through.

[0080] On the upper surface of the cover member 260-1, a disk-seatsurface 222 is provided to have a flat surface so that the disk-seatsurface 222 makes surface contact with the disk 1 (FIG. 2) where thedisk 1 is received on the engagement projection 220. A friction member223 aids the disk-seat surface 222 to prevent the disk 1 from idlyrotating by increasing frictional force between the cover member 260-1and the disk 1.

[0081] Preferably, the turntable 200 a comprises a magnet 230 so thatthe disk 1 (FIG. 2) is retained on the disk-seat surface 222 due tomagnetic interaction between the magnet 230 and the clamper 300 (FIG.2). The magnet 230 is inserted in an installation hole 221 formed at theengagement projection 220.

[0082] The movable members 270 comprise one of a plurality of the rigidbodies 271, a fluid 272 such as a liquid, and the plurality of rigidbodies 271 and the fluid 272. The movable members 270 move away from therotation center of the shaft 130 according to respective centrifugalforces developed where the main body 210-1 rotates.

[0083]FIG. 15 is an exploded perspective view illustrating an example inwhich the movable members 270 comprise a plurality of rigid bodies 271which are contained in the cavity 250. The rigid bodies 271 areinstalled to freely roll or slide in the cavity 250 so that thepositions of the rigid bodies 271 are determined by respectivecentrifugal forces developed where the main body 210-1 rotates.

[0084] The rigid 271 is constructed as one of a sphere shaped rigid body430-1, cylindrical shaped rigid body 430-2, conical frustum shaped rigidbody 430-3, sectorial pillar shaped rigid body 430-4, or the likeaccording to various embodiments thereof. The shape of the rigid body271 may be changed to another shape as long as the rigid body 271 freelymoves in the cavity 250.

[0085] A fluid 272 may be included so that the movable members 270comprise the fluid 272 and the rigid bodies 271. Since the fluid 272 hasa greater contacting area with the main body 210-1 and the cover member260-1 than the rigid bodies 271, where the fluid 272 is used in thecavity 250 together with the rigid bodies 271, the eccentric center ofmass of the disk 1 (FIG. 2), which causes vibrations internal to thedisk drive, is more effectively compensated.

[0086] Here, an amount of fluid 272 may be just enough to provide acoating of about several-μm thickness on each rigid body 271. In thiscase, the fluid 272 serves as a lubricant to reduce friction between therigid bodies 271 and the inner surfaces of the main body 210-1 and thecover member 260-1 instead of a substantial part in a balancingoperation.

[0087] Since the rigid bodies 271 may not roll well due to interactionbetween adjacent rigid bodies 271, where the rigid bodies 271 are underthe influence of a magnetic field, it is preferable that the rigidbodies 271 are made of a non-magnetic material so that the rigid bodies271 are not influenced by the magnetic field of the magnet 230. Thus,the rigid bodies 271 move smoothly, according to the rotation of theturntable 200 a and the position of eccentric center of mass of the disk1 (FIG. 2).

[0088] Preferably, the rigid body 271 is made of an antioxidantmaterial, or coated with an antioxidant material so that the rigid body271 is prevented from erratically rolling or sliding in the cavity 250due to oxidation and corrosion of the rigid body 271. The anti-oxidationcoating is formed by plating the rigid body 271 with a thin layer ofzinc, nickel and/or chromium on a base metal such as a carbon steel, oran iron-chromium alloy. In addition, the rigid body 271 may be made of amaterial whose oxide particle oxidated in air is sufficiently fine tonot affect the movement of the rigid body 271.

[0089] The fluid 272 may be employed as the movable members 270 withoutemploying the rigid bodies 271. In this case, the cavity 250 is sealedwith the cover member 260-1 so that the fluid 272 does not leak out.

[0090] A shape of a diametrical section of the cavity 250 formed by themain body 210-1 and the cover member 260-1 may be one of the shapesdescribed above with reference to the self compensating balancer 400,that is, a rectangular shape 450-1, a dumbbell shape 450-2, a hyperbolicshape 450-3, a half-hyperbolic shape 450-3, or an elliptical shape450-4, as shown in FIGS. 11 through 14.

[0091] Preferably, the main body 210-1 and the cover member 260-1 aremade of non-magnetic materials so as to prevent the influence ofmagnetic forces interacting with the rigid bodies 271. That is, the mainbody 210-1 and the cover member 260-1 may be made of non-magneticmetallic materials such as tungsten carbide, a copper-beryllium alloy,Hastelloy C-276, zirconia (ZrO₂), brass, aluminum, an austeniticstainless steel (YHD50), SUS300, SUS304, SUS316, or the like, a ceramicmaterial such as silicon nitride, or a synthetic resin material. Inaddition, the rigid body 271 may be made of a non-magnetic material suchas bronze, brass, or copper, and, then, be plated with nickel, chromiumand/or the like as a surface treatment.

[0092] Also, the main body 210-1 is preferably made of an antioxidantmaterial or is coated with an antioxidant material. The antioxidantmaterial includes SUS 300, a ceramic material, a synthetic resinmaterial, or the like. The antioxidant coating is formed by plating athin layer of zinc, nickel and chromium, or the like on a base metalsuch as a carbon steel, or a iron-chromium alloy.

[0093] A second embodiment 200 b of a self-compensating-dynamic-balancerintegrated turntable according to the present invention will bedescribed with reference to FIG. 17. The second embodiment 200 b issimilarly constructed as the first embodiment 200 a of theself-compensating-dynamic balancer integrated turntable.

[0094] In the second embodiment 200 b, the rotation shaft 130 of aspindle motor 100 is inserted through an engagement hole 211 formedthrough a main body 210-2 of the turntable 200 b, and is fixed in anupper hole 212 of a cover member 260-2 after traversing the cavity 250.However, since the movable members 270 move toward peripheral portionsof the turntable 200 a due to respective centrifugal forces where theturntable 200 a rotates, the rotation shaft 130 does not interfere withmovements of the movable members 270.

[0095]FIG. 18 illustrates a third embodiment 200 c of aself-compensating-dynamic-balancer integrated turntable according to thepresent invention. In the third embodiment 200 c of theself-compensating-dynamic-balancer integrated turntable of the presentinvention, a turntable main body 210-2 is not separately provided asshown in FIG. 17. In the self-compensating-dynamic-balancer integratedturntable 200 c, the cavity 250 which encloses the movable members 270is incorporated integral with a rotor 120 of a spindle motor 100. Thespindle motor 100 comprises a stator 140 and the rotor 120. The spindlemotor 100 is installed on a motor base 110 a, which is different fromthe first and second embodiments, 200 a and 200 b, respectively. A rimportion 121 is provided at the rotor 120 to form the cavity 250 whichencloses the movable members 270. In this manner, aself-compensating-dynamic-balancer integrated turntable is realizedwithout preparing a separate main body of a turntable. Examples of themovable members 270 and examples of a sectional shape of the cavity 250are the same as those of the first and second embodiments 200 a and 200b of the self-compensating-dynamic-balancer integrated turntable. FIG.18 also illustrates an embodiment of aself-compensating-dynamic-balancer integrated spindle motor turntable500 where the self-compensating-dynamic-balancer turntable 200 c isintegrated into the rotor of the spindle motor 100.

[0096] Although the first, second and third embodiments of theself-compensating-dynamic-balancer integrated turntable are illustratedby incorporating the self-compensating-dynamic-balancer shown in FIG.11, it will be readily appreciated by those skilled in the art that thescope of the invention includes incorporating any of theself-compensating-dynamic-balancers described above with reference toFIGS. 4 through 14 as a self-compensating-dynamic-balancer member of theself-compensating-dynamic-balancer integrated turntables 200 a, 200 band 200 c.

[0097] A self-compensating-dynamic-balancer integrated clamper 300 aaccording to embodiments of the present invention will be described indetail with reference to FIGS. 19 through 22.

[0098] As shown in FIG. 2, a self-compensating-dynamic-balancerintegrated clamper 300 a of the present invention is positioned by abracket 301 to hold a disk 1 seated on a turntable 200 (FIG. 2). Thebracket 301 is fixed to a deck base 50 by other structure (not shown).

[0099] Referring to FIGS. 19 and 20, a first embodiment of aself-compensating-dynamic-balancer integrated clamper 300 a according tothe present invention comprises a cylindrical clamper main body 310-1provided with a cavity 350, a pressing member 320, an intermediate covermember 330, movable members 370, and a cover member 360. The pressingmember 320 is installed in a receiving hole 311 formed at the clampermain body 310-1 to press a disk 1 (FIG. 2) seated on the turntable 200(FIG. 2). The intermediate cover member 330 blocks the receiving hole311 after the pressing member 320 is installed. The movable members 370are disposed in the cavity 350, and move toward peripheral portions ofthe cavity 350 according to respective centrifugal forces where theclamper main body 310-1 rotates. The cover member 360 covers an openingof the clamper main body 310-1 to enclose the cavity 350.

[0100] The intermediate cover member 330 and the cover member 360 arefixed to the damper main body 310-1 by using an adhesive, grooves andprojections formed at corresponding positions, respectively, or screws.Since such fixing methods are well-known, detailed descriptions thereofwill be omitted.

[0101] The opening of the clamper main body 310-1 may be formed over thewhole upper portion of the main body 310, as shown in FIGS. 19 and 20,or may be formed at a portion thereof to have dimensions that enableinsertion of the movable members 370 therethrough. Alternatively, thepressing member 320 may be a yoke member 321.

[0102] Where a magnet 230 is provided on the turntable 200 (FIG. 2), ina similar manner as shown for turntables 200 a, 200 b and 200 c as shownin FIGS. 15 through 18, the yoke member 321 presses against the disk 1(FIG. 2) due to interaction between the yoke member 321 and the magnet230.

[0103] A second embodiment 300b of a self-compensating-dynamic-balancerintegrated clamper of the present invention is shown in FIG. 21. In thesecond embodiment 300 b, a pressing member 320 a performs a similarfunction as pressing member 320. The pressing member 320 a comprises apressing plate 324 and an elastic member 325. The pressing plate 324 isinstalled under a lower surface of a clamper main body 310-2 to bemovable vertically. The elastic member 325 is interposed between theclamper main body 310-2 and the pressing plate 324 so that the pressingplate 324 elastically presses the disk 1 (FIG. 2). Thus, where theclamper main body 310-2 approaches the turntable 200, the pressingmember 320 a holds the disk 1 placed on the turntable 200 and theself-compensating-dynamic-balancer integrated clamper 300 b rotatestogether with the turntable 200.

[0104] In the embodiments shown in FIGS. 20 and 21, the movable members370 comprise a plurality of rigid bodies 371 which are radially movableaway from the rotation center of the clamper main body 310-1 (310-2)within the cavity 350 according to respective centrifugal forces wherethe clamper main body 310-1 (310-2) rotates.

[0105]FIGS. 19 through 21 show examples of aself-compensating-dynamic-balancer integrated clamper 300 a (300 b) inwhich a plurality of rigid bodies 371 are contained in the cavity 350 asthe movable members 370. The rigid bodies 371 roll or slide freely sothat positions of the rigid bodies are determined by respectivecentrifugal forces where the main body 310-1 (310-2) rotates.

[0106] Preferably, the rigid bodies 371 have one of a spherical shape, acylindrical shape, a conical frustum shape or a sectorial pillar shape,such as for example the spherical shape 430-1, the cylindrical shape430-2, the conical frustum shape 430-3, or the sectorial pillar shape430-4 as described with reference to FIGS. 7, 8, 9 and 10, respectively.However, the shape of the rigid body 371 may be changed to another shapeas long as the rigid body 371 is free to move in the cavity 350.

[0107] A third embodiment 300 c of a self-compensating-dynamic-balancerintegrated clamper according to the present invention is shown in FIG.22. In the third embodiment 300 c, the movable members 370 comprise afluid 372 and the plurality of the rigid bodies 371. Since the fluid 372has a greater contacting area with the clamper main body 310-1 and thecover member 360 than the rigid bodies 371, where the fluid 372 is usedin the cavity 350 together with the rigid bodies 371, eccentric mass ofthe disk 1 (FIG. 2) which causes internal vibrations is more effectivelycompensated.

[0108] Preferably, the rigid bodies 371 are made of a non-magneticmaterial so that the rigid bodies 371 are not influenced by the magneticfield of a magnet 230 (FIG. 15). Where the rigid bodies 371 arenon-magnetic, the rigid bodies 371 move depending on the rotation of theclamper main body 310 and the position of the eccentric center of massof the disk 1 (FIG. 2).

[0109] Preferably, the rigid body 371 is made of an antioxidantmaterial, or coated with an antioxidant material so that the rigid body371 can be prevented from erratically rolling and sliding in the cavity350 due to oxidation and corrosion of the rigid body 371. Alternatively,the rigid body 371 may be made of a material whose oxide particleoxidated in air is fine enough to not affect the movement of the rigidbody 371.

[0110] Alternatively, only the fluid 372 may be employed as the movablemembers 370 in either of the first, second and third embodiments, 300 a,300 b and 300 c, respectively, without employing the rigid bodies 371.

[0111] A shape of a sectional view of the cavity 350 taken through therotation center of the clamper main body 310-1 may be a rectangularshape 450-1, a dumbbell shape 450-2, a hyperbolic shape 450-3, ahalf-hyperbolic shape 450-4, or an elliptical shape 450-5, as suchshapes are described with reference to FIGS. 11, 12, 13A, 13B and 14,respectively.

[0112] Preferably, the clamper main body 310-1 (310-2), the intermediatecover member 330, and the cover member 360 are made of non-magneticmaterials so that they are not influenced by magnetic interaction withthe rigid bodies 371. Preferably, the clamper main body 310-1 (310-2) ismade of an antioxidant material, or coated with an antioxidant material.

[0113] A self-compensating-dynamic-balancer integrated spindle motor fora disk player according to the present invention will be described indetail with reference to FIGS. 23 through 25. FIGS. 23-25 illustrate afirst embodiment 100 a thereof and FIG. 25 illustrates a secondembodiment thereof.

[0114] The self-compensating-dynamic-balancer-integrated spindle motor100 a according to the present invention is constructed to be fixedlyinstalled on a deck plate to rotate a turntable 200 fixed to therotation shaft 130 of the spindle motor in a similar manner as spindlemotor 100 shown in FIG. 2.

[0115] Referring now to FIG. 23, the self-compensating-dynamic-balancerintegrated spindle motor 100 a of the present invention comprises amotor base 110, a rotation shaft 130, a stator 140, a rotor 120, firstand second bearings 132 and 134, a cylindrical case 121 having a cavity150 with a cylindrical side wall 151 fixed to the rotor 120, and movablemembers 170 disposed within the cavity 150 of the case 121.

[0116] The motor base 110 is fixed to the deck plate 70 (FIG. 2), andhas a through hole 111 at a center portion thereof. The first and secondbearings 132 and 134 together with the rotation shaft 130 are fittedinto the through hole 111.

[0117] The stator 140 is fixedly installed under a lower surface 113 ofthe motor base 110, and comprises a yoke 141 facing the rotor 120, and acoil portion 143 disposed at an inner side of the yoke 141. The firstand second bearings 132 and 134 are disposed between the through hole111 and the rotation shaft 130, and support the rotation shaft 130 inradial directions and an axial direction. The first and second bearings132 and 134 are provided as a pair, and are disposed in the through hole111 while being spaced a predetermined distance apart from each other.The first bearing 132 has an inner race 132 a which is fixed to therotation shaft 130 and an outer race 132 b which is fixed to the throughhole 111, to prevent the rotation shaft 130 from moving radially andaxially. The second bearing 134 is slidably inserted into the throughhole 111, to prevent the rotation shaft 130 from slanting. An elasticmember 131 is disposed in the through hole 111 between the first andsecond bearings 132 and 134 so that rotational vibrations of the rotor120 are prevented from being transferred to the motor base 110. Inconsideration of positional preciseness of the rotation shaft duringhigh-speed rotation, metal bearings are preferably employed as the firstand second bearings 132 and 134. Alternatively, another type ofbearings, such as, for example, ball bearings or dynamic-air-pressurebearings may be employed.

[0118] The rotor 120 is fixed to one end of the rotation shaft 130, anda magnet 123 is installed in the rotor 120 to face the yoke 141. Here, afixing member 133 is further provided at the engagement portion betweenthe rotor 120 and the rotation shaft 130 to prevent the rotation shaft130 from being separated from the rotor 120 or rotating idly.

[0119] The case 121 is fixed to the rotor 120 using an adhesive orgrooves and projections which are formed at positions corresponding toeach other. The movable members 170 comprise a plurality of rigid bodies171 which are allowed to radially move away from the rotation centeraccording to respective centrifugal forces thereof where the rotor 120rotates.

[0120]FIGS. 23 and 24 show one example of aself-compensating-dynamic-balancer integrated spindle motor in which aplurality of rigid bodies 171 are contained in the cavity 150 of thecase 121 as the movable members 170. The rigid bodies 171 are installedto roll or slide freely so that positions of the rigid bodies aredetermined by respective centrifugal forces where the rotor 120 rotates.Preferably, the rigid bodies 171 have one of a spherical shape, acylindrical shape, a conical frustum shape or a sectorial pillar shape,such as for example the spherical shape 430-1, the cylindrical shape430-2, the conical frustum shape 430-3, or the sectorial pillar shape430-4 as described with reference to FIGS. 7, 8, 9 and 10, respectively.However, the shape of the rigid body 171 may be changed to another shapeas long as the rigid body 171 is free to move in the cavity 150.

[0121] In the second embodiment of theself-compensating-dynamic-balancer spindle motor as shown in FIG. 25,the fluid 172 may be included together with the rigid bodies 171 as themovable members 170. Since the fluid 172 has a greater contacting areawith the inner surfaces of the case 121 than the rigid bodies 171, wherethe fluid 172 is used in the cavity 150 together with the rigid bodies171, the eccentric center of mass of the disk 1 (FIG. 2) which causesinternal vibrations is more effectively compensated.

[0122] Preferably, the rigid bodies 171 are made of a non-magneticmaterial such as for example, one of the non-magnetic materialsdescribed above in reference to rigid bodies 271, so that the rigidbodies 171 are not influenced by the magnetic field of the magnet 123.Thus, the rigid bodies 171 move depending on the rotation of the rotor120 and the position of the eccentric center of mass of the disk 1 (FIG.2).

[0123] The rigid bodies 171 are preferably made of an antioxidantmaterial, or coated with an antioxidant material so that the rigidbodies 171 are prevented from erratically moving in the case 121 due tooxidation and corrosion of the rigid bodies 171. Alternatively, therigid bodies 171 may be made of a material whose oxide particle oxidatedin air is fine so as not to affect the movement of the rigid bodies 171.

[0124] Alternatively, only the fluid 172 may be employed as the movablemembers 170 without employing the rigid bodies 171.

[0125] A shape of a sectional view of the cavity 150 taken through therotation center of the cylindrical case 121 may be a rectangular shape450-1, a dumbbell shape 450-2, a hyperbolic shape 450-3, ahalf-hyperbolic shape 450-4, or an elliptical shape 450-5, as suchshapes are described with reference to FIGS. 11, 12, 13A, 13B and 14,respectively.

[0126] Preferably, the case 121 is made of a non-magnetic material so asto prevent the influence of magnetic forces interacting with the rigidbodies 171. In addition, it is preferable that the case 121 is made ofan antioxidant materials, or coated with an antioxidant material, suchas for example, the materials and coatings identified above withreference to the main body 412.

[0127] Referring again to FIG. 2, a second embodiment 10 a of aself-compensating-dynamic-balancer integrated disk player according tothe present invention comprises a deck base 50, a deck plate 70, dampermembers 60, a spindle motor 100, an optical pickup 75, and a clamper300, as described above with reference to FIG. 2, and one of theself-compensating-dynamic-balancer integrated turntables 200 a and 200 bdescribed with reference to FIGS. 15 through 17. The second embodimentof the self-compensating-dynamic-balancer integrated disk player issimilarly constructed as the disk player 10 of FIG. 2 and differs inthat the self-compensating-dynamic-balancer 400 schematically shown inFIG. 2 is integrated into the one turntable 200 a or 200 b.

[0128] A third embodiment of a self-compensating-dynamic-balancerintegrated disk player according the present invention comprises a deckbase 50, a deck plate 70, damper members 60, a spindle motor 100, aturntable 200 and an optical pickup 75, as described above withreference to FIG. 2, and one of a self-compensating-dynamic-balancerintegrated clamper 300 a, 300 b and 300 c described with reference toFIGS. 19 through 22. The third embodiment of theself-compensating-dynamic-balancer integrated disk player is similarlyconstructed as the disk player 10 of FIG. 2 and differs in that theself-compensating-dynamic-balancer 400 schematically shown in FIG. 2 isintegrated into the one clamper 300 a, 300 b or 300 c.

[0129] A fourth embodiment 10 c of a self-compensating-dynamic-balancerintegrated disk player according to the present invention comprises adeck base 50, a deck plate 70, clamper members 60, a turntable 200, anoptical pickup 75, and a clamper 300, as described above with referenceto FIG. 2, and one of the self-compensating-dynamic-balancer integratedspindle motors 100 a and 100 b described with reference to FIGS. 23through 25. Thus, in the fourth embodiment of theself-compensating-dynamic-balancer integrated disk player theself-compensating-dynamic-balancer 400 schematically shown in FIG. 2 isintegrated into the one spindle motor 100 a or 100 b.

[0130] A fifth embodiment 10 d of a self-compensating-dynamic-balancerintegrated disk player according to the present invention comprises adeck base 50, a deck plate 70, clamper members 60, a turntable 200, anoptical pickup 75, and a clamper 300, as described above with referenceto FIG. 2, and the self-compensating-dynamic-balancer integrated spindlemotor turntable 500 described with reference to FIG. 18. The fifthembodiment is constructed similar to the second embodiment 10 a as shownin FIG. 2 and differs in that the integrated spindle motor turntable 500replaces the turntable 200 a (200 b) and the spindle motor 100.

[0131] In summary, in a self-compensating-dynamic-balancer disk playerof the present invention, a self-compensating dynamic balancer 400 maybe integrated into any rotating member such as the turntable 200, theclamper 300, and the spindle motor 100, and, may be employed in two ormore rotating members taking into consideration the rotational speed ofthe disk 1 (FIG. 2), the range of allowable tolerances of the eccentriccenter of mass, and the like.

[0132] Now, the vibration reduction effect of a disk player employing aself-compensating dynamic balancer 400 according to the presentinvention, incorporated in self-compensating-dynamic-balancer integratedrotating members, such as for example, the turntable 200 a, 200 b or 200c, the clamper 300 a 300 b or 300 c, the spindle motor 100 a or 100 b,and the spindle motor turntable 500, will be described with reference toFIGS. 26 and 27.

[0133] Where the rotational frequency of the disk 1 is less than thenatural frequency of the deck plate, as shown in FIG. 26, positions(P_(i), i=1, 2, 3, and 4) of the eccentric center of mass m_(e) of thedisk 1, and positions (P_(i)′, i=1, 2, 3, and 4) of the weight center ofthe self-compensating dynamic balancer including the movable members andthe cover member, that is, a compensating mass m_(c) are positionedopposite to the revolution center C with respect to positions (C_(i),i=1, 2, 3, and 4) of the rotation shaft, respectively. Therefore, theradius of revolution of the rotation shaft becomes greater.

[0134] On the other hand, where the rotational frequency of the disk 1is much greater than the natural frequency of the deck plate, and thedisk 1 rotates substantially at normal speed, as shown in FIG. 27, therevolution center C and positions (P_(i), i=1, 2, 3, and 4) of theeccentric mass m_(e) of the disk 1 are positioned at the same side, andpositions (P_(i)′, i=1, 2, 3, and 4) of a compensating mass m_(c) arepositioned at the opposite side due to centrifugal forces, respectively.Therefore, since unbalance due to the eccentric mass m_(e) of the disk 1is counterbalanced by the compensating mass m_(c), the radius ofrevolution of the rotation shaft reduces markedly, and internalvibrations of the deck plate due to the eccentric mass m_(e) of the disk1 can be limited.

[0135] A self-compensating-dynamic-balancer integrated disk player, aself-compensating-dynamic-balancer integrated spindle motor,self-compensating-dynamic-balancer integrated members rotated by thespindle motor, which are configured as described above according to thepresent invention can effectively minimize internal vibrations due tothe rotation of the disk by counterbalancing the eccentric mass of thedisk which causing the internal vibrations with forces which aregenerated by the movable members due to centrifugal forces and act fromthe revolution center of the disk to outward in the cylindrical cavity.

[0136] A damper member of weak strength may be employed in a disk playeraccording to the present invention so that external impact is dampenedeffectively. Accordingly, a disk player according to the presentinvention is appropriate for very high speed (greater than 6-speed)CD-ROM and DVD-ROM drives.

[0137] Although a few embodiments of the present invention have beenshown and described, it would be appreciated by those skilled in the artthat changes may be made in these embodiments without departing from theprinciples and spirit of the invention, the scope of which is defined inthe claims and their equivalents.

What is claimed is:
 1. A self-compensating-dynamic-balancer integratedclamper for pressing a disk placed on a turntable of a disk player, theclamper comprising: a clamper main body provided with a cavity; apressing member installed at the clamper main body for pressing thedisk; movable members movably disposed in the cavity of the clamper mainbody; and a cover member joined to an opening of the main body toenclose the cavity.
 2. The self-compensating-dynamic-balancer integratedclamper as claimed in claim 1, wherein the movable members comprise aplurality of rigid bodies and a fluid.
 3. Theself-compensating-dynamic-balancer integrated clamper as claimed inclaim 1, wherein the turntable comprises a magnet, a lower surface ofthe clamper main body contacts the disk, and the pressing member is ayoke installed at an inner lower portion of the clamper main body so asto press the disk by an interactive magnetic force between the yoke andthe turntable.
 4. The self-compensating-dynamic-balancer integratedclamper as claimed in claim 1, wherein the pressing member comprises: apressing plate which is movable vertically, and an elastic memberinterposed between the clamper main body and the pressing plate.
 5. Theself-compensating-dynamic-balancer integrated clamper as claimed inclaim 2, wherein: the clamper main body comprises a cylindrical innerside wall and an another wall which form the cavity, and each rigid bodycomprises a spherical shape which is free to roll within the clampermain body.
 6. The self-compensating-dynamic-balancer integrated clamperas claimed in claim 1, wherein a shape of a section of the cavitycomprises a rectangular shape.
 7. The self-compensating-dynamic-balancerintegrated clamper as claimed in claim 2, wherein: the clamper main bodycomprises a cylindrical inner side wall and an another wall which formthe cavity, and each rigid body comprises a cylindrical shape which isfree to roll in contact with the cylindrical inner sidewall.
 8. Theself-compensating-dynamic-balancer integrated clamper as claimed inclaim 2, wherein: the clamper main body comprises a cylindrical innerside wall and an another wall which form the cavity, and each rigid bodycomprises a conical frustum shape which is free to roll between theanother wall and the cover member.
 9. Theself-compensating-dynamic-balancer integrated clamper as claimed inclaim 2, wherein: the clamper main body comprises a cylindrical innerside wall and an another wall which form the cavity, and each rigid bodycomprises a sectorial pillar shape which is permitted to slide betweenthe another wall and the cover member.
 10. Theself-compensating-dynamic-balancer integrated clamper as claimed inclaim 1, wherein a shape of a section of the cavity comprises a dumbbellshape.
 11. The self-compensating-dynamic-balancer integrated clamper asclaimed in claim 1, wherein a shape of a section of the cavity comprisesa hyperbolic shape which has a narrow portion at a center portion of thehyperbolic shape and wider portions toward edge sides of the hyperbolicshape.
 12. The self-compensating-dynamic-balancer integrated clamper asclaimed in claim 1, wherein a shape of a section of the cavity comprisesa half-hyperbolic shape.
 13. The self-compensating-dynamic-balancerintegrated clamper as claimed in claim 1, wherein a shape of a sectionof the cavity comprises an elliptical shape which has a wide portion ata center portion of the elliptical shape and narrower portions towardedge sides of the elliptical shape.
 14. Theself-compensating-dynamic-balancer integrated clamper as claimed inclaim 1, wherein the movable members comprise a plurality of rigidbodies.
 15. The self-compensating-dynamic-balancer integrated clamper asclaimed in claim 1, wherein the movable members comprise a fluid.
 16. Aself-compensating-dynamic-balancer integrated clamper for pressing adisk placed on a turntable of a disk player, the clamper comprising: aclamper main body which rotates with the disk, the main body comprising:a cylindrical inner wall, first and second transverse walls whichcooperate with the inner wall to form a cavity, and a plurality ofspherical shaped rigid bodies disposed in the cavity and free to movewithin the cavity including movement across a center of rotation of themain body; and a pressing member installed at the clamper main body forpressing the disk.
 17. The self-compensating-dynamic-balancer integratedclamper as claimed in claim 16, further comprising a fluid disposed inthe cavity along with the spherical shaped rigid bodies.